Tumor Markers — Clinical Relevance

A 68-year-old woman with a history of colorectal cancer presents with abdominal pain. Serum CEA is 8.5 ng/mL (normal <5) and CA 19-9 is 95 U/mL (normal <37). Which single finding best distinguishes metastatic colorectal cancer from benign colonic pathology in this patient?

A 35-year-old woman with a family history of medullary thyroid carcinoma (MTC) presents for screening. She is asymptomatic with normal thyroid examination. Serum calcitonin is elevated at 45 pg/mL (normal <10 pg/mL). Which investigation is most appropriate as the next step to localize the MTC?

A 52-year-old man with a history of cirrhosis presents with a 3 cm hepatic nodule on imaging. Serum alpha-fetoprotein (AFP) is 450 ng/mL. Regarding tumor markers in hepatocellular carcinoma (HCC), all of the following statements are correct EXCEPT:

Regarding the clinical utility and biochemical properties of common tumor markers, all of the following are true EXCEPT:

A 52-year-old man from Delhi presents with a 3-month history of progressive abdominal distension, early satiety, and weight loss of 8 kg. On examination, he has hepatomegaly (3 cm below costal margin), ascites, and a firm left supraclavicular lymph node. Ultrasound abdomen shows a heterogeneous mass in the gastric fundus with ascites. Serum AFP is 450 IU/mL (normal <20), and CEA is 8 ng/mL (normal <5). Upper endoscopy with biopsy confirms gastric adenocarcinoma. Which tumor marker is most useful for monitoring treatment response and detecting recurrence in this patient?